Almost perfect!
Rick, it's safe to say that you took all the capabilities of Flash and put them to excellent use. I noticed that several reviewers compared this to the Heavy Metal films. *Side Note: I've only seen 2000 and it wasn't as bad as its detractors say it was in spite of the numerous mistakes made in the animation production.* Of course this also reminds me of the following:
-Dirty Pair, a series of novels that was adapted into an anime and a comic by Dark Horse. (You should check that out some time.)
-Burning Angels, a TurboGrafx-16 game that wasn't released stateside judging by the cockpit of her spaceship.
-Don Bluth's Titan A. E.
With that out of the way, on with the actual critique:
Graphically speaking, it may not be up to par with what Spike Valentine or Adam Phillips have done, but you managed to put gradients, shaded colors, Tweens, frame-by-frame, etc. to excellent use. Plus, I like the ammount of detail that you put into this even though it lags on older computers. However, I think this could have used some 3D models for the spacecraft. On the other hand, I don't know how good you are at 3D modeling. Speaking of the spacecraft, on one hand, they have a more utilitarian function to them, at the cost of the aesthetics. Soundwise, the music was suitable for the mood you were aiming for unlike that of Arrogancy and Minushi. Although voices would have been nice, I'd rather take subtitles over the shitty voice acting that those aforementioned Flash series are synonymous with. The sound effects are good, but they could have used a bit more diversity. Then there is the directing, which compensates for whatever flaws that this had. To put it another way, the pacing was perfect for what you were aiming for, and a lot of people on here could learn something from you.
What I liked about this:
-The length and the directing
-The animation, while not the best, gets the point across
-Something fresh
-The Music selection
-The character and creature design. Plus, I liked the blood variation.
What I didn't like:
-The spacecraft, while functional, could have been designed better.
-Swift 3D/Milkshape 3D would have helped. Then again, It might not.
-Could have used some subtitles
-The plot could use some improvements, but that's what interquels are for.
-The sound effects, while passable, could have used some more variety.
Overall: In spite of its flaws, this is going to get a nine out of ten.